Experimental Test Facility Research Articles

Design of Pump as Turbine Experimental Test Facility

This paper presents the design process of experimental test facility for pump as turbine hydropower system. Three design possibilities that related to the PAT condition of operation was developed and analyzed by using CFD Software. It is found that the First Variant with a straight flow to the PAT will produce higher velocity, which is needed to generate more rotation of the shaft generator, in order to generate more electric power. The strength of PAT construction was analyzed by using FEM software. It was found that the maximum stress is 6 MPa and can be concluded that the construction is appropriate to the design requirement.

Preliminary CFD Assessment of an Experimental Test Facility Operating with Heavy Liquid Metals

The CFD analysis of a Venturi nozzle operating in LBE (key component of the CIRCE facility, owned by ENEA) is presented in this paper. CIRCE is a facility developed to investigate in detail the fluid-dynamic behavior of ADS and/or LFR reactor plants. The initial CFD simulations have been developed hand in hand with the comparison with experimental data: the test results were used to confirm the reliability of the CFD model, which, in turn, was used to improve the interpretation of the experimental data. The Venturi nozzle is modeled with a 3D CFD code (STAR-CCM+). Later on, the CFD model has been used to assess the performance of the component in conditions different from the ones tested in CIRCE: the performance of the Venturi is presented, in terms of pressure drops, for various operating conditions. Finally, the CFD analysis has been focused on the evaluation of the effects of the injection of an inert gas in the flow of the liquid coolant on the performance of the Venturi nozzle.

EXPERIMENTAL STUDIES OF A DYNAMIC LATERAL STABILIZATION SYSTEM

[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT The purpose of the ongoing experimental research of a dynamic lateral stabilization system is to identify permanent magnets-based design solutions that provide lateral stability of a magnetic levitation (maglev) vehicle. The obtained results are useful in designing an energy independent system, i . e. one that uses no electromagnets or superconductors thanks to which a reduction in the mass and dimensions of the system can be achieved. The practical significance of this study consists in the possibility of applying the researched principles in the design of magnetic levitation transport systems. Keywords: magnetic levitation transport, experimental test facility, lateral stabilization, magnetic pole, Halbach array.

Validation of the CATHARE 1-D and 3-D reflood models against FEBA and ACHILLES experimental tests

This paper presents results of a code validation activity that has been carried out at the University of Pisa within the EC-funded NURESAFE project, aimed to assess CATHARE2 v2.5_3 Mod3.1 code capabilities to simulate scenarios featuring reflood conditions. For such purpose, experimental data available from FEBA and ACHILLES separate-effect test facilities was used.In order to set-up a reference calculation model, rigorous sensitivity studies have been performed for each of the selected experimental test facilities. Quantitative analysis of the results has been carried out for all of the considered tests, using the Fast Fourier Transform Based Method (FFTBM) for accuracy quantification of code predictions.The calculations of experimental tests of ACHILLES facility have been performed with CATHARE2 v2.5_3 mod 3.1 using both 1-D and 3-D models. The non-regression of the results predicted by such code was successfully checked through qualitative and quantitative comparison with results obtained by the one of previous code versions: CATHARE2 v2.5_2 mod 7.1.An assessment of the capabilities of the new CATHARE3 v1.3.13 code to simulate reflood phenomena using both two- and three-field 1-D models has then been carried out, based on the same ACHILLES tests. Simulations by CATHARE3 (three-field) exhibit faster quenching than CATHARE2, mainly due to the presence of the droplet field enhancing the heat exchange from the fuel rod simulators.The performed qualitative analysis has shown the ability of CATHARE2 code to capture the main features of the reflood phenomena using appropriate modeling. Nonetheless, the quantitative analysis shows a systematic underprediction of the peak cladding temperature and faster quenching in the majority of FEBA and ACHILLES tests.

A fast response miniature probe for wet steam flow field measurements

Modern steam turbines require operational flexibility due to renewable energies’ increasing share of the electrical grid. Additionally, the continuous increase in energy demand necessitates efficient design of the steam turbines as well as power output augmentation. The long turbine rotor blades at the machines’ last stages are prone to mechanical vibrations and as a consequence time-resolved experimental data under wet steam conditions are essential for the development of large-scale low-pressure steam turbines. This paper presents a novel fast response miniature heated probe for unsteady wet steam flow field measurements. The probe has a tip diameter of 2.5 mm, and a miniature heater cartridge ensures uncontaminated pressure taps from condensed water. The probe is capable of providing the unsteady flow angles, total and static pressure as well as the flow Mach number. The operating principle and calibration procedure are described in the current work and a detailed uncertainty analysis demonstrates the capability of the new probe to perform accurate flow field measurements under wet steam conditions. In order to exclude any data possibly corrupted by droplets’ impact or evaporation from the heating process, a filtering algorithm was developed and implemented in the post-processing phase of the measured data. In the last part of this paper the probe is used in an experimental steam turbine test facility and measurements are conducted at the inlet and exit of the last stage with an average wetness mass fraction of 8.0%.

An experimental method for controlled generation and characterization of microchannel slug flow boiling

This study uses high-speed imaging to characterize microchannel slug flow boiling using a novel experimental test facility that generates an archetypal flow regime suitable for high-fidelity characterization of key hydrodynamic and heat transfer parameters. Vapor and liquid phases of the fluorinated dielectric fluid HFE-7100 are independently injected into a T-junction to create a saturated two-phase slug flow, thereby eliminating the flow instabilities and flow-regime transitions that would otherwise result from stochastic generation of vapor bubbles by nucleation from a superheated channel wall. Slug flow boiling is characterized in a heated, 500μm-diameter borosilicate glass microchannel. A thin layer of optically transparent and electrically conductive indium tin oxide coated on the outside surface of the microchannel provides a uniform heat flux via Joule heating. High-speed flow visualization images are analyzed to quantify the uniformity of the vapor bubbles and liquid slugs generated, as well as the growth of vapor bubbles under heat fluxes ranging from 30W/m2 to 5160W/m2. A method is demonstrated for measuring liquid film thickness from the visualizations using a ray-tracing procedure to correct for optical distortions. Characterization of the slug flow boiling regime that is generated demonstrates the unique ability of the facility to precisely control and quantify hydrodynamic and heat transfer characteristics. The experimental approach demonstrated in this study provides a unique platform for the investigation of microchannel slug flow boiling transport under controlled, stable conditions suitable for model validation.

The Effect of Rotor Casing on Low-Pressure Steam Turbine and Diffuser Interactions

The present study aims to investigate the interaction between a last-stage steam turbine blade row and diffuser. This work is carried out using computational fluid dynamics (CFD) simulations of a generic last-stage low-pressure (LP) turbine and axial–radial exhaust diffuser attached to it. In order to determine the validity of the computational method, the CFD predictions are first compared with data obtained from an experimental test facility. A computational study is then performed for different design configurations of the diffuser and rotor casing shapes. The study focuses on typical flow features such as effects of rotor tip leakage flows and subsequent changes in the rotor–diffuser interactions. The results suggest that the rotor casing shape influences the rotor work extraction capability and yields significant improvements in the diffuser static pressure recovery.

Acoustic modeling of perforated concrete using the dual porosity theory

Perforated concrete shows nowadays a high potential for many construction and building engineering applications. This work is devoted to the analysis of the acoustic properties of perforated concrete made from arlite lightweight aggregates. Concrete produced from these materials is an environmentally friendly alternative to traditional materials and offers a higher durability, excellent strength-to-weight ratio and low cost. In particular, it is shown that the acoustic behavior of perforated concrete can be modeled using a dual porosity approach based on the knowledge of the non-acoustic properties of the matrix granular material and geometrical data. To this end, various non-perforated and perforated samples were prepared and characterized in an experimental test facility, their acoustic properties being determined through the transfer function impedance tube method. Experimental and estimated results related to the acoustic properties of a number of prepared specimens are presented, showing a good agreement. Results suggest that this approach is suitable for practical design of such materials as part of noise control systems.

Validating under-resolved turbulence intensities for PIV experiments in canonical wall-bounded turbulence

The discrepancy between measured turbulence intensity obtained from experiments in wall-bounded turbulence and the fully resolved reference results (usually from DNS datasets) are often attributed to spatial resolution issues, especially in PIV measurements due to the presence of spatial averaging within the interrogation region/volume. In many cases, in particular at high Reynolds numbers (where there is a lack of DNS data), there is no attempt to verify that this is the case. There is a risk that attributing unexpected PIV statistics to spatial resolution, without careful checks, could mask wider problems with the experimental setup or test facility. Here, we propose a robust technique to validate the under-resolved PIV obtained turbulence intensity profiles for canonical wall-bounded turbulence. This validation scheme is independent of Reynolds number and does not rely on empirical functions. It is based on arguments that (1) the viscous-scaled small-scale turbulence energy is invariant with Reynolds number and that (2) the spatially under-resolved measurement is sufficient to capture the large-scale energy. This then suggests that we can estimate the missing energy from volume-filtered DNS data at much lower Reynolds numbers. Good agreement is found between the experimental results and estimation profiles for all three velocity components, demonstrating that the estimation tool successfully computes the missing energy for given spatial resolutions over a wide range of Reynolds numbers. A database for a canonical turbulent boundary layer and associated MATLAB function are provided that enable this missing energy to be calculated across a range of interrogation volume sizes, so that users do not require access to raw DNS data. This methodology and tool will provide PIV practitioners, investigating canonical wall-bounded turbulent flow with a convenient check of the effects of spatial resolution on a given experiment.

Experimental and numerical analyses on the effect of increasing inflow temperatures on the flow mixing behavior in a T-junction

Thermal degradation of piping induced by high cycle thermal fatigue (HCTF) is of significant importance as operating Nuclear Power Plants (NPP) become older and lifetime extension activities are initiated. In particular, HCTF incidents related to turbulent thermal mixing of fluids in a T-junction piping system are not well understood and could not be adequately monitored using common thermocouple instrumentation. To investigate this phenomenon, an experimental T-junction test facility was commissioned at the University of Stuttgart, known as the Fluid Structure Interaction (FSI) test facility. The paper presents the experimental investigation and the corresponding numerical validation using the large eddy simulation (LES) method to study T-junction flow mixing. Three experimental test cases are investigated with temperature differences (∆T) of 51.5K (Case 1), 76K (Case 2) and 97K (Case 3) between the mixing fluids. A constant mass flow rate ratio (main/branch) of 4:1 is maintained in all the investigated cases. Flow mixing is observed to be incomplete in all the cases, resulting in a thermally stratified flow with an oscillating stratification layer downstream of the T-junction. Mean temperature and root mean square (RMS) temperature fluctuations predicted by LES in the mixing region are found to be in good agreement with measurement data, with the exception of few positions. Amplitudes of temperature fluctuations are observed to be higher near the stratification layer, ranging from 6.3–9.9% of ∆T. Power spectral density (PSD) analyses of temperature fluctuations indicate no dominant frequency (spectral peak) under prevailing flow conditions, an important factor in thermal fatigue analysis, and the energy of these fluctuations are mainly contained in the frequency range of 0.1–2Hz for all the investigated cases. LES is performed using the CFD software ANSYS CFX 14.0.

Measurement of convective heat transfer coefficients in a randomly packed bed of silica gel particles using IHTP analysis

The purpose of this research is to determine the convective heat transfer coefficient (ht) for airflow through two randomly packed beds of microporous silica gel particles of nearly uniform diameter (i.e., for the average diameter of 1.60 and 2.58mm). The experimental test facility was developed to induce a transient step change in the inlet uniform airflow while the temperature was measured at several locations within the silica gel beds (x/L=0.29, 0.48, 0.69). The transient test data were simulated numerically using the volume averaging method for air flow through a homogeneous packed bed of particles for a range of Reynolds numbers (40<Redh<100). The convective heat transfer coefficient was determined by using the numerical inverse method to minimize the difference between the simulated and experimental temperature profiles. The sensitivity analysis stated that the thermocouple placed at the middle of the test section (x/L=0.48) had the highest sensitivity during the first 400s of transient testing. Using the ht values obtained by the inverse calculations, a good agreement is obtained within the experimental uncertainty limits for the experimental and numerical temperature temporal profiles at different locations within the beds; but the agreement is best using the transient temperature data at x/L=0.48. Based on the ht values, a new correlation between Nusselt number and Reynolds number is presented with lower uncertainty (the maximum uncertainty of ±30%) compared to the correlations in the literatures. It was found that the proposed correlation is in agreement with the data in literature within their uncertainty bounds.

Evaluating the Thermal and Electrical Performance of Several Uncovered PVT Collectors with a Field Test

Recently, there has been a lot of interest in PV thermal systems, which generate both heat and power. Within the WenSDak project, several companies and research institutes work together to (further) develop several uncovered PVT collectors. The outdoor performance of prototypes of these collectors is being evaluated in an outdoor test setup. The three types of uncovered PVT collectors in this paper can be distinguished as an un-insulated add-on PVT collector, a PVT collector with insulation at the back and a building integrated PVT collector.In this paper, we will describe the experimental outdoor field test facility used for measuring the electrical and thermal performance. Furthermore, the results of the steady state analysis and typical collector curves are presented. In the next phase of the project, results of this field test will be used for dynamic simulations of the annual electrical and thermal energy yields for typical system designs and heat loads in the Netherlands.

Blast Valve Design and Related Studies : A Review

The protective structures required for performing critical operations are vulnerable to the blast and shock loads of advanced weapons. A blast valve is an important component of such structures for ventilation during normal conditions and for protection from blast/ shock during explosion. In this paper, various aspects of blast valve design and related studies are briefly reviewed. The concept and effects of blast wave, blast impact, numerical modelling and deformation of circular plate (one of the critical components of blast valve) have been discussed. The merits and demerits of sensing mechanisms viz. remote and direct sensing are discussed. The leakage of blast pressure during finite closing period of the valve (one of the critical problems) and the shock tube as a major experimental facility for testing of blast valves are briefly discussed.

Test facility for nuclear planetology instruments

An experimental facility for testing and calibrating nuclear planetology instruments has been constructed in partnership between the Space Research Institute (Moscow) and the Joint Institute for Nuclear Research. A model of Martian soil with a size of 3.82 × 3.21 m2 and an overall mass of about 30 t is assembled from silicate glass. Glass is chosen in order to imitate absolutely dry soil close in composition to the Martian one. The heterogeneous model allows one to imitate the average elemental composition of Martian soil in the best possible way by adding layers of the necessary materials to it. Near-surface water ice is simulated by polyethylene layers buried at different depths within the glass model. A portable neutron generator is used as the neutron source for testing active neutron and gamma spectrometers. The facility is radiation-hazardous and is thus equipped with interlock and radiation monitoring systems in accordance with the effective regulations.

Laboratory simulation of heat exchange for liquids with Pr &gt; 1: Heat transfer

Liquid metals are promising heat transfer agents in new-generation nuclear power plants, such as fast-neutron reactors and hybrid tokamaks—fusion neutron sources (FNSs). We have been investigating hydrodynamics and heat exchange of liquid metals for many years, trying to reproduce the conditions close to those in fast reactors and fusion neutron sources. In the latter case, the liquid metal flow takes place in a strong magnetic field and strong thermal loads resulting in development of thermogravitational convection in the flow. In this case, quite dangerous regimes of magnetohydrodynamic (MHD) heat exchange not known earlier may occur that, in combination with other long-known regimes, for example, the growth of hydraulic drag in a strong magnetic field, make the possibility of creating a reliable FNS cooling system with a liquid metal heat carrier problematic. There exists a reasonable alternative to liquid metals in FNS, molten salts, namely, the melt of lithium and beryllium fluorides (Flibe) and the melt of fluorides of alkali metals (Flinak). Molten salts, however, are poorly studied media, and their application requires detailed scientific substantiation. We analyze the modern state of the art of studies in this field. Our contribution is to answer the following question: whether above-mentioned extremely dangerous regimes of MHD heat exchange detected in liquid metals can exist in molten salts. Experiments and numerical simulation were performed in order to answer this question. The experimental test facility represents a water circuit, since water (or water with additions for increasing its electrical conduction) is a convenient medium for laboratory simulation of salt heat exchange in FNS conditions. Local heat transfer coefficients along the heated tube, three-dimensional (along the length and in the cross section, including the viscous sublayer) fields of averaged temperature and temperature pulsations are studied. The probe method for measurements in a flow is described in detail. Experimental data are designated for verification of codes simulating heat exchange of molten salts.

Development of experimental test facilities for validation of multistream plate finheat exchanger design codes

Compact plate-fin heat exchangers (PFHE) having very high effectiveness (>0.95) are key equipment of modern helium liquefaction/refrigeration systems. Effectiveness (e) of these heat exchangers strongly influences the overall system performance. Apart from basic fluid film resistances, various secondary parameters such as axial heat conduction (AHC) through the heat exchanger metal matrix, parasitic heat in-leak from surroundings, variation in fluid/metal properties and flow mal-distribution etc need to be considered while sizing/rating such high effectiveness PFHE. Need of multiple streams in a single heat exchanger further complicates thermal designs. In-house codes are developed at BARC/IIT Bombay for rating of such high effectiveness PFHEs. For experimental performance evaluation of PFHEs, their characterization at various operating conditions and validation of in-house developed numerical codes, a dedicated closed loop experimental test facility is developed. Development of the dedicated closed loop experimental test facility is presented in this paper along with initial test results.

Cyber Defense of Rotating Machinery Using an Integrated ‘Fuse’ Bearing

A new concept is proposed for protection against cyber-attacks aiming to create excessive loads that will eventually result in irreversible damage to critical rotating machines. This novel approach is used as an additional defense layer of cyber protection to prevent hostile entities from breaking into the control system of the critical machines. A relatively small bearing is used as the weak link, or the mechanism, in the critical system. This mechanism allows rapid life degradation under harmful regimes, which leads to early detection of attack and finally to prevention of catastrophic damage to a critical machine. The detection of the fuse degradation process is based on techniques of machine health monitoring via vibrations signatures. An analytical model was developed, allowing to design the 'fuse bearing'. The model examines the response of the fuse bearing, through its life degradation rate, by simulating a wide range of attack scenarios. The model integrates sub models: bearing life estimation models and a dynamic response of mechanical rotating machines model. In addition, a set of fatigue life experiments were conducted on a designated experimental test facility with the purpose of proving the early damage detection ability of the fuse bearing using vibration analysis.

Installation of spectrally selective imaging system in RF negative ion source.

A spectrally selective imaging system has been installed in the RF negative ion source in the International Thermonuclear Experimental Reactor-relevant negative ion beam test facility ELISE (Extraction from a Large Ion Source Experiment) to investigate distribution of hydrogen Balmer-α emission (Hα) close to the production surface of hydrogen negative ion. We selected a GigE vision camera coupled with an optical band-path filter, which can be controlled remotely using high speed network connection. A distribution of Hα emission near the bias plate has been clearly observed. The same time trend on Hα intensities measured by the imaging diagnostic and the optical emission spectroscopy is confirmed.

FEASIBILITY STUDY OF UNDERGROUND SALT CAVERNS IN WESTERN NEWFOUNDLAND: EXPERIMENTAL AND FINITE ELEMENT INVESTIGATION OF CREEP-INDUCED DAMAGE

Underground caverns in rock salt deposits are the most secure disposal method and a type of gas-storing facility. Gas storage plays a vital role in ensuring that a strategic relationship is secured between an established energy infrastructure provider and a midstream energy company. The Fischells Brook area is a pillow-shaped body of salts located in the St. George's Bay area of southwest Newfoundland, which has three layers of salt beds, and is capable of excavating caverns for the storage purposes. The development of cavern facilities requires the stability analysis through numerical models and experimental facilities. This work was motivated to examine the engineering feasibility of the salt cavern characteristics in this area, and to investigate its stability under creep behavior. An experimental test facility was developed to investigate the constitutive parameters governing the creep of rock salt, and the constitutive parameters were implemented into a developed finite element model to investigate the stability of the cavern over a 5-year period. Also a stress-based dilatancy failure envelope was developed to interpret the results of the numerical model, and to conduct sensitivity analyses for different design scenarios. The design recommendations developed in this study will be implemented as a key part of an engineering feasibility study for underground caverns in salt deposits in western Newfoundland.

A computer-controlled experimental facility for krypton and xenon adsorption coefficient measurements on activated carbons

An automated experimental test facility, intended specifically for qualification of the krypton and xenon adsorption properties of activated carbon samples, was designed and constructed. The experimental apparatus was designed to allow an on-line control of the main physical parameters influencing greatly the adsorption property of activated carbon. The measurement of the adsorption coefficient, based upon the elution curve method, can be performed with a precision better than 5% at gas pressure values ranging from atmospheric pressure up to 9bar and bed temperature from 0 up to 80°C. The carrier gas flow rate can be varied from 40 up to 4000Ncm3min−1 allowing measurement of dynamic adsorption coefficient with face velocities from 0.3 up to 923cmmin−1 depending on the gas pressure and the test cell being used. The moisture content of the activated carbon can be precisely controlled during measurement, through the relative humidity of the carrier gas.